Rat terrier mix male

I need to rehome my rat terrier mix male dog. He is a good dog I'm just unable to take care of him properly. He needs somebody that can give him attention and train him. He need a yard to run in and to be walked. I've only had him a short time and don't know about him. I think someone hit him or something he can be scared for no reason at times but he is smart and can learn if taught. In Willis. I am asking $40 .